Blind

ABSTRACT

A blind comprising a number of thin blades arranged in parallel to one another, wherein said blades are respectively mounted at opposite ends thereof in a manner of being constantly stretched and are adjustably rotated about their axes altogether for a same angle, whereby the blades made of thin flat plates can be held straight and uncollapsed condition with no support in the way of the span of the blades.

1451 sept. 1s, 1973Y 11111111.11 states Patent Tachikawa PENTEU SEPI 81973 SHEU 2 0F 3 PAIENIEU sm e ma snm 3 or FIG.

BLIND BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to a blind composed of a number of thin blades arranged in parallel to one another.

2. Description of the Prior Art The blind of the abovementioned type is conventionally known and properly used for the purpose of controlling the sight and/or lighting of rooms. In the conventional blinds of the abovementioned type, especially the ones wherein the blades are arranged horizontally, the thin blades, which are mostly formed of synthetic resin, are suspended by two or more rows of string works which are adapted to suspend a number of thin blades in parallel rows with a controlled angle of inclination. In these conventional blinds, the thin blades are usually formed to have a curved cross section for the purpose of increasing the stiffness of the relatively elongated blades made of a relatively soft synthetic resin, because, otherwise, the thin blades will be irregularly curved or unstably sway due to high flexibility thereof when they are suspended, especially horizontally, by two or more rows of string works.

Because of the curved cross section of the blades, the blades are, as a matter of fact, not so thin as the plate of which they are really made and present a substantial thickness which causes gloominess of the window covered by the blind even when the blades are fully opened or fully adapted to the direction of sight.

SUMMARY OF TI-IE INVENTION Accordingly, it is the main object of this invention to provide a blind of the type of being composed of a number of thin blades arranged in parallel to one another, which, however, presents a very high opening ratio as compared with conventional ones when it was fully opened so that it causes no gloominess of the window covered by the blind.

Another object of this invention is to provide a blind in which the blades are suspended by no conventional string works which cross the open area of the window and intercept the sight through the window.

A further object of this invention is to provide a blind which can be incorporated into a window frame as a semipermanent structure with its long-durable structure.

The abovementioned objects are accomplished, according to this invention, by a blind comprising number of thin blades arranged in parallel to one another, rotatable shafts each being adapted to carry an end of each one of said blades, bearing means carrying said rotatable shafts along two opposing frames of a window in a manner that said rotatable shafts are rotatable about their axes as well as shiftable along their axes, resilient means adapted to apply resilient force to said rotatable shafts in the direction of stretching said blades, and linkage means adapted to rotate all of said rotatable shafts simultaneously for a same angle.

Since, according to this invention, the thin blades are always kept in a stretched condition, there occurs no irregular curving or large amplitude of swaying of the blades even if the blades are formed of a thin and flexile flat plate. Therefore, the blades composing the blind according to this invention may be formed as flat strips which present just the same apparent thickness as the actual thickness thereof.

Since the blades are mounted at opposite ends thereof in a stretched manner, they can keep a straigh span therebetween. Therefore, no supporting means is required in the way of the span between the opposite ends of the blades.

The linkage means adapted to rotate all of the rotatable shafts simultaneously for a same angle, which are operatively linked to the rotatable shafts supported by the bearing means arranged along two opposing frames of a window may preferably be constituted as a structure incorporated into a window frame as a semipermanent structure, because they are preferably composed of levers, connecting rods, or chains, racks and pinions, ete., such as exemplarly shown in the embodiment described hereinunder with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing,

FIG. 1 is a front view of an embodiment of the blind assembly according to this invention;

FIG. 2 is a plan view of a lower end frame of the blind assembly shown in FIG. 1 along line II-II in FIG. l;

FIG. 3 is a side view of a lower end portion of the blind assembly along line III-III in FIG. 1 in a condition where the blades are opened to be substantially horizontal;

FIG. 4 is a side view of the same kind as FIG. 3, wherein, however, the blades are fully closed;

FIG. S is a perspective view showing the parts of engagement of the blade and the rotatable shaft; and

FIG. 6 is a perspective view of a lower portion of the blind assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the following, this invention will be described more particularly of a preferred embodiment with reference to the accompanying drawing.

Referring to FIG. l, reference numerals l designate two opposing side frames of a window firmly connected with a bottom frame 2 and a top frame (not shown).

`Across the opening area of the window, there are extended a number of blades 3 arranged in parallel and especially horizontally in this embodiment. Each blade 3 is supported at opposite ends thereof by holding pins 4 in a manner of being elastically stretched as described in more detail hereinunder. Each holding pin 4 comprises a head portion 5 adapted to engage with the end of the blade 3 and a shaft portion 6 received by one of bearing holes 7 formed in the frames l in a manner of being rotatable about its axis as well as shiftable in its axial directions. Adjacent the free end of the shaft porton 6, the holding pin 4 carries a lever 8 firmly mounted thereon, which in turn carries a pin 9 threaded into an opening provided adjacent the free end thereof. A compression coil spring l0 is mounted on the shaft portion 6 of each holding pin 4 over a length extending between the 'bearing portion arounol the bearing hole 7 and the lever 8 so that the holding pin 4 is resiliently held toward the frame 1.

As shown more clearly in FIGS. 3, 4 and 6, the pins 9 are respectively received in relatively elongated openings ll of shift plates l2 which are respectively received in the frames l to be shiftable up and down along guide grooves 13 provided in the frames 1. The vertical position of the plates l2 is controlled by racks 14, each being mounted at the bottom end of the plate l2. The racks 14 are respectively in meshing engagement with pinions l which are carried by a shaft 16 extending along the bottom frame 2 and rotatably mounted therein. At a central portion of the shaft 16, it also carries a worm pinion 17 adapted to be driven by a worm 18, which in turn is carried by a shaft 19 adapted to be rotated by hand via a handle 20.

FIG. 5 shows the .manner of mounting the end of the blade 3 to the head portion 5 of the holding pin 4. The end of the blade 3 is formed to present a bead portion 3a adapted to be received in a groove 5a formed in the head portion S of the holding pin 4. The groove 5a opens with a slit 5b through which the blade 3 extends when the bead 3a was engaged into the groove 5a and was fixed there by a clamp pin 2l.

ln operation, when the handle is rotated in clockwise direction, the worm pinion l7 is driven in clockwise direction seen in FIGS. 3 and 4, whereby the rack 14 is moved downward while turning the levers 8 clockwise seen in FIGS. 3 and 4 until the condition shown in FIG. 4 of the blades 3 being fully closed is attained. Conversely, when the handle 20 is rotated in anticlockwise direction, the levers 8 are turned anticlockwise seen in FIGS. 3 and 4, whereby the blades 3 can be fully opened as shown in FIG. 3.

l claim: i

l. A blind comprising a number of thin horizontal blades each having a bead at each end arranged in parallel to each another, rotatable shafts including a head portion having a slot therein engaging with the bead each head portion carrying an end of each one of said blades, bearing means carrying said rotatable shafts along two opposing frames of a window in a manner that said rotatable shafts are rotatable about their axes as well as shiftable along their axes, elastic means comprising a compression coil spring mounted on the shaft to apply elastic force to said rotatable shafts in the direction of stretching said blades, thereby preventing obstruction of view through the window due to a sagging curvature in the blades, and linkage means adapted to rotate all of said rotatable shafts simultaneously for a same angle.

2. A blind according to claim l, wherein said linkage means comprises levers each mounted to said rotatable shaft and shift plates adapted to engage with free ends of said levers so that said levers are turned for a same amount according to a shifting of said shift plates.

3. A blind according to claim 2, wherein said levers and said shift plates are engaged with each other by way of pins each mounted to the free end of said lever at one end thereof and received in an elongated opening formed in said shift plate adjacent other end thereof.

4. A blind according to claim 2, wherein said shift plates are shifted by racks mounted thereto, said racks being in meshing engagement with pinions.

5. A blind according to claim 4, wherein said pinions are mounted on a common shaft.

6. A blind according to claim 5, wherein said common shaft is adapted to be driven by hand via worm gear means.

, i: a: :s :c 

1. A blind comprising a number of thin horizontal blades each having a bead at each end arranged in parallel to each another, rotatable shafts including a head portion having a slot therein engaging with the bead each head portion carrying an end of each one of said blades, bearing means carrying said rotatable shafts along two opposing frames of a window in a manner that said rotatable shafts are rotatable about their axes as well as shiftable along their axes, elastic means comprising a compression coil spring mounted on the shaft to apply elastic force to said rotatable shafts in the direction of stretching said blades, thereby preventing obstruction of view through the window due to a sagging curvature in the blades, and linkage means adapted to rotate all of said rotatable shafts simultaneously for a same angle.
 2. A blind according to claim 1, wherein said linkage means comprises levers each mounted to said rotatable shaft and shift plates adapted to engage with free ends of said levers so that said levers are turned for a same amount according to a shifting of said shift plates.
 3. A blind according to claim 2, wherein said levers and said shift plates are engaged with each other by way of pins each mounted to the free end of said lever at one end thereof and received in an elongated opening formed in said shift plate adjacent other end thereof.
 4. A b1ind according to claim 2, wherein said shift plates are shifted by racks mounted thereto, said racks being in meshing engagement with pinions.
 5. A blind according to claim 4, wherein said pinions are mounted on a common shaft.
 6. A blind according to claim 5, wherein said common shaft is adapted to be driven by hand via worm gear means. 